[Mapping of the B Cell Neutralizing Epitopes on ED III of Envelope Protein from Dengue Virus]

Dengue virus (DENV) envelope [E] protein is the major surface protein of the virions that indued neutralizing antibodies. The domain III of envelope protein (EDIII) is an immunogenic region that holds potential for the development of vaccines; however, the epitopes of DENV EDIII, especially neutralizing B-cell linear epitopes, have not been comprehensively mapped. We mapped neutralizing B-cell linear epitopes on DENV-1 EDIII using 27 monoclonal antibodies against DENV-1 EDIII proteins from mice immunized with the DENV-1 EDIII. Epitope recognition analysis was performed using two set of sequential overlapping peptides (16m and 12m) that spanned the entire EDIII protein from DENV-1, respectively. This strategy identified a DENV-1 type- specific and a group-specific neutralizing epitope, which were highly conserved among isolates of DENV-1 and the four DENV serotypes and located at two regions from DENV-1 E, namely amino acid residues 309-320 and 381-392(aa 309-320 and 381-392), respectively. aa310 -319(310KEVAETQHGT319)was similar among the four DENV serotypes and contact residues on aa 309 -320 from E protein were defined and found that substitution of residues E309 , V312, A313 and V320 in DENV-2, -3, -4 isolates were antigenically silent. We also identified a DENV-1 type-specific strain-restricted neutralizing epitope, which was located at the region from DENV-1 E, namely amino acid residues 329-348 . These novel type- and group-specific B-cell epitopes of DENV EDIII may aid help us elucidate the dengue pathogenesis and accelerate vaccine design.